The present invention relates to a solid-state image sensing device and an electronic device having therein a solid-state image sensing device and, more particularly, relates to a technique for realizing higher picture quality.
An electronic device having therein an image sensor (solid-state image sensing device) is widely spread. The electronic device receives an operation of the user and generates a still image, a moving image, and the like. The user shares still images and the like generated by using those electronic devices with others user via a network or the like and performs communicates. In recent years, a mobile device having a camera module is being spread and chances that a high-quality image is generated are being increased.
An example of the solid-state image sensing device is a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The CMOS image sensor includes, for example, a plurality of unit pixels arranged two-dimensionally. Each of the unit pixels has at least a photodiode, a transfer gate for transferring charges accumulated in the photodiode to a floating diffusion (FD) region, and a reset transistor for resetting charges in the floating diffusion region. In the image sensor, at the signal reading time, first, a signal processor reads a signal according to voltage in the floating diffusion region from each of the pixels (reading of signal level) and, next, reads, from each of the pixels, a signal according to a voltage when the charges in the floating diffusion region are reset (reading of reset level). The signal processor eliminates noise on the basis of the difference between the signal level and the reset level.
In the CMOS image sensor, to maintain synchronism of signal charge accumulation periods, a global shutter operation is performed. In the case of sequentially initializing the floating diffusion region before charge transfer on the row unit basis, there is a case that a voltage drop in the power supply of a reset transistor for initializing the floating diffusion region and a crosstalk between a reset signal line for supplying a reset signal to pixels in adjacent rows and the floating diffusion region occur.
To realize higher picture quality of such a solid-state image sensing device, for example, Japanese Unexamined Patent Application Publication No. 2012-129799 (patent literature 1) describes that in a CMOS image sensor, driving of a floating diffusion region by a reset transistor is controlled every plural rows which are not adjacent to each other in a pixel array unit before transfer of charges by a transfer gate.